LCD serial backpacks

[timseven]

I am new on this forum and also on programming PICs. I was looking for a program that helps me turn my parallel LCD into a serial. That’s what Mr. Darrel Taylor’s program does on “LCD Serial backpacks post #16. I wonder first if I could use his program on a 16F628 because the compiler doesn’t like it as is. Second, on what pin of which port should I connect the serial input on that 16F628 that will drive the parallel LCD. Sorry for these silly questions but I really would like to learn how to do that. Thanks.

[Darrel Taylor]

I am new on this forum and also on programming PICs. I was looking for a program that helps me turn my parallel LCD into a serial. That’s what Mr. Darrel Taylor’s program does on “LCD Serial backpacks post #16. I wonder first if I could use his program on a 16F628 because the compiler doesn’t like it as is. Second, on what pin of which port should I connect the serial input on that 16F628 that will drive the parallel LCD. Sorry for these silly questions but I really would like to learn how to do that. Thanks.

It'll work on a 628.
Check out this thread

Instant Interrupts - Revisited
http://www.picbasic.co.uk/forum/showthread.php?t=3251

The first post shows where to get the files.
And the rest of the thread will answer many questions.

hth,

[timseven]

Thank you sir.

[timseven]

Well, after I read a group of posts I started to understand what your interest of introducing these new interrupts was. I am not very familiar with interrupts but I want to take advantage of this new approach. First I did was to try to play with your Blink program and at compilation time (16F628) I got an error: “Variable wsave3 position request 416 beyond Ram_End 335” I have look every where for an explanation of this error with no luck. Please, advice.

[Darrel Taylor]

There is a section in the DT_INTS-14.bas file that has to be adjusted for the chip you are compiling for.
I wish I could make it automatic, but there's no way to do that.

For a 16F628, it doesn't have any General Purpose RAM in BANK3. So you have to comment out the wsave3 variable in this section.

wsave       var byte    $20     SYSTEM      ' location for W if in bank0
;wsave       var byte    $70     SYSTEM     ' alternate save location for W 
                                            ' if using $70, comment out wsave1-3

' --- IF any of these three lines cause an error ?? ---------------------------- 
'       Comment them out to fix the problem ----
' -- It depends on which Chip you are using, as to which variables are needed --
wsave1      var byte    $A0     SYSTEM      ' location for W if in bank1
wsave2      var byte    $120    SYSTEM      ' location for W if in bank2
;wsave3      var byte    $1A0    SYSTEM      ' location for W if in bank3
' ------------------------------------------------------------------------------

The 628 also has Access RAM at address $70 which can be accessed from any bank.
So commenting everything and uncommenting the $70 variable will work too.
Either way will work ... take your pick.

;wsave       var byte    $20     SYSTEM      ' location for W if in bank0
wsave       var byte    $70     SYSTEM     ' alternate save location for W 
                                            ' if using $70, comment out wsave1-3

' --- IF any of these three lines cause an error ?? ---------------------------- 
'       Comment them out to fix the problem ----
' -- It depends on which Chip you are using, as to which variables are needed --
;wsave1      var byte    $A0     SYSTEM      ' location for W if in bank1
;wsave2      var byte    $120    SYSTEM      ' location for W if in bank2
;wsave3      var byte    $1A0    SYSTEM      ' location for W if in bank3
' ------------------------------------------------------------------------------

[timseven]

I'll report to you. Thanks

[timseven]

Well, beautiful. I comment out the 3 wsaves and everything came out as planned. I tested the 628 on my breadboard and the led blinked as expected. After that triumph I load your Serialin (I called Parallel to Serial) program and compiled it. I got one error only
“Error [118] C:\program~1\mecanic~1\mcs\parallel~3 asm 200:Overwriting previous address contents(2007)” As always I try to find that error on the posts and I did but I don’t understand how to fix it. Thanks.